Q. Why is a steel boiler superior to an iron boiler? 
A. Because it is much lighter and stronger.

Q. Does boiler plate become stronger or weaker as it becomes heated?  A. It becomes tougher or stronger as it is heated, till it reaches a temperature Of 550 degrees when it rapidly decreases its power of resistance as it is heated beyond this temperature.

Q. How do you account for this?  A. Because after you pass the maximum temperature of 550 degrees, the more you raise the temperature the nearer you approach its fusing point when its tenacity or resisting power is nothing.

Q. What is the degree of heat necessary to fuse iron? 
A. 2912 degrees.

Q. Steel? 
A. 2532 degrees.

Q. What class of boilers are generally used in a threshing engine?  A. The flue boiler and the tubular boiler.

Q. About what amount of heating and grate surface is required per horse power in a flue boiler.  A. About 15 square feet of heating surface and 3/4 square feet of grate surface.

Q. What would you consider a fair evaporation in a flue boiler?  A. Six pounds of water to I pound of coal.

Q. How do these dimensions compare in a tubular boiler.  A. A tubular boiler will require I/4 less grate surface, and will evaporate about 8 pounds of water to I pound of coal.

Q. Which do you consider the most available? 
A. The tubular boiler.

Q. Why? 
A. It is more economical and is less liable to “collapse?”

Q. What do you mean by “collapse?”
A. It is a crushing in of a flue by external pressure.

Q. Is a tube of a large diameter more liable to collapse than one of small diameter?  A. Yes.

Q. Why? 
A. Because its power of resistance is much less than a tube
of small diameter.

Q. Is the pressure on the shell of a boiler the same as on the tubes?  A. No.

Q. What is the difference? 
A. The shell of boiler has a tearing or internal pressure
while the tubes have a crushing or external pressure.

Q. What causes an explosion?  A. An explosion occurs generally from low water, allowing the iron to become overheated and thereby weakened and unable to withstand the pressure.

Q. What is a “burst?” A. It is that which occurs when through any defect the water and steam are allowed to escape freely without further injury to boiler.

Q. What is the best way to prevent an explosion or burst?  A. (I) Never go beyond a safe working pressure. (2) Keep the boiler clean and in good repair. (3) Keep the safety valves in good shape and the water at its proper height.

Q. What is the first thing to do on going to your engine in the morning?  A. See that the water is at its proper level.

Q. What is the proper level? 
A. Up to the second gauge.

Q. When should you test or try the pop valve? 
A. As soon as there is a sufficient pressure.